1. Field of the Invention
The present invention relates to a split type connecting rod, and more particularly, to a split type connecting rod with a bearing located inside of a crank-pin hole.
2. Description of the Related Art
A split type connecting rod is formed such that a large end portion is fractured and divided into a rod portion and a cap portion a long a splitting plane including the shaft center of a crank-pin hole, and the rod portion and the cap portion are coupled by coupling bolts, and a metal bearing is generally located on the inner circumferential surface of the crank-pin hole.
In general, this metal bearing has been split into a rod-side portion and a cap-side portion along the splitting plane and when such a split type metal bearing is disposed within the inner circumferential surface of the crank-pin hole, a bearing locking groove is formed in the inner circumferential surface so to extend in the circumferential direction so that a locking lug protruding from the rear surface (outer circumferential surface) of the metal bearing is locked by the bearing locking groove in order to determine a position of the metal bearing (e.g., see the Unexamined Japanese Patent Publication No.HEI 6-74237).
However, the conventional split type connecting rod has a problem in that the metal bearing is easily rotated in the circumferential direction by an external force, and in order to prevent burning caused by this problem, a reliable lubrication structure is required. In particular, a motorcycle engine which tends to be used at high speed revolutions has a problem in that a large amount of deformation occurs at the large end portion and the amount of rotation of the metal bearing is likely to increase accordingly.